In the motor vehicle field, it is well known to maintain the voltage which is supplied to the on-board electrical network by the alternator of the vehicle at a predetermined set value, independently from the speed of rotation of the engine or the electrical consumption of the equipment, by means of a regulation device known as a “regulator”.
Nowadays, motor vehicle parts manufacturers have developed very high-performance alternators by implementing electronic power systems controlled by circuits which use digital techniques, based in particular on the use of microprocessors or microcontrollers.
Unlike the former bimetal regulators, which operated around a fixed regulation voltage, independently from the operating mode of the vehicle, modern electronic regulation devices take advantage of the processing capacities of the electronics in order to receive variable set values transmitted by a control unit of the engine, for the purpose of optimising the collection of torque, according to the production of electrical energy necessary.
The engine control unit can communicate with the regulator of the alternator, and command a particular operating mode of the latter.
The information which is transmitted in return to the engine control unit is very often information relating to an excitation current of the alternator.
In the most modern regulators, such as the one developed by the company VALEO EQUIPEMENTS ELECTRIQUES MOTEUR described in patent application FR2938135, the regulation circuit is in the form of an ASIC (acronym for “Application Specific Integrated Circuit”) which is connected by external interconnections (known as bonding) to a circuit of tracks of a brush-holder, such as to form an assembly in a single piece known as the “regulator brush-holder”, which can be integrated on a rear bearing of the alternator.
This regulator is programmable, and can therefore be adapted to a plurality of applications, and comply with various specifications of the motor vehicle manufacturers, without significant modifications.
However, its single-chip architecture does not protect it against failure, and, in this case, since the regulation function is no longer ensured, excess voltage is generated on the on-board network of the vehicle by the alternator.